The present invention relates to an improved retractable caster assembly.
In my earlier U.S. Pat. No. 4,845,804 issued Jul. 11, 1989, a retractable caster for difficult-to-manage cases, crates and the like was described. That caster assembly is designed to be either surface mounted or flush mounted on the bottom of large and bulky or heavy containers or cases, to facilitate their handling. Thus, when such cases or containers, fitted with such retractable caster assemblies, are placed in conditions where they would be subjected to irregular or sudden motion, the wheels are retracted. On the other hand, when it is desired to move such containers or cases, the wheels may be withdrawn into operative position so that the containers could be moved by rolling on the caster wheels.
The caster construction described and illustrated in that patent comprises a frame having a planar base and sides circumscribing the base to form a cavity having an opening. The frame is secured at an appropriate location on the bottom of the container, case or other object in question. A rigid flap is provided secured to the frame by a hinge, to swing about an axis between open position perpendicular to the base and closed position, parallel to but spaced from the base, to close at least a portion of the cavity opening. A wheel is rotatably supported by a wheel support assembly secured to the flap. A portion of the wheel extends beyond the lower edge of the flap when in operative position. An articulated strut is secured to and extends between a portion of the frame and the wheel support assembly. The strut folds when the wheel is in retracted position so that the wheel, wheel support and strut are fitted within the cavity between the base and the flap in closed position. A pin lock is provided, to pass through apertures in overlapping portions of the strut, to lock the strut in operative position.
While such a caster construction has proven to be remarkably effective in operation, certain improvements have been found to be desirable. More particularly, the strut lock arrangement requires a worker to place his or her hand within the cavity of the assembly frame to remove or insert the pin, with consequent danger of injury, particularly considering the weight of many of the containers to which such assemblies are secured.
A more secure method of locking the strut in its open, operative position, is also been felt to be a desirable goal and is thus an object of the present invention. It is a further object of the present invention to provide a mechanism which will enable the release of that locking mechanism, to enable the strut to be folded and wheel elevated into retracted position, minimizing the need for a worker to place a hand within the assembly frame cavity. It is a further object of the present invention to provide a reliable, effective mechanism for releasably securing the caster wheel in its retracted position, again which mechanism can be operated safely by a worker from outside the assembly frame cavity.